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United States Patent |
6,232,029
|
Kushino
,   et al.
|
May 15, 2001
|
Process for preparing flash fixation toner and master batch for use in said
process
Abstract
A method for the production of a flash fixing toner containing at least a
binding resin, a coloring agent, and an infrared absorbent, which method
is characterized by the steps of blending a master batch containing said
infrared absorbent at a concentration 3-50 times as thick as that intended
to be incorporated ultimately in the toner, with other toner components,
thereby forming a toner composition containing said infrared absorbent at
a requested concentration, melting and kneading said toner composition,
cooling the molten toner composition, and then pulverizing the solidified
toner composition.
Inventors:
|
Kushino; Mitsuo (Hyogo, JP);
Matsumoto; Makoto (Osaka, JP);
Yodoshi; Takashi (Abiko, JP)
|
Assignee:
|
Nippon Shokubai Co., Ltd. (Osaka, JP)
|
Appl. No.:
|
297946 |
Filed:
|
July 7, 1999 |
PCT Filed:
|
September 10, 1998
|
PCT NO:
|
PCT/JP98/04075
|
371 Date:
|
July 7, 1999
|
102(e) Date:
|
July 7, 1999
|
PCT PUB.NO.:
|
WO99/13382 |
PCT PUB. Date:
|
March 18, 1999 |
Foreign Application Priority Data
Current U.S. Class: |
430/137.18 |
Intern'l Class: |
G03G 009/08 |
Field of Search: |
430/137,126,109
|
References Cited
U.S. Patent Documents
4539284 | Sep., 1985 | Barbetta et al. | 430/110.
|
4824948 | Apr., 1989 | Stark et al. | 540/125.
|
5432035 | Jul., 1995 | Katagiri et al. | 430/106.
|
5582950 | Dec., 1996 | Katagiri et al. | 430/137.
|
5618648 | Apr., 1997 | Horikoshi et al. | 430/126.
|
Foreign Patent Documents |
0 412 494 A1 | Feb., 1991 | EP | .
|
60-57857 | Apr., 1985 | JP | .
|
60-63546 | Apr., 1985 | JP | .
|
63-295578 | Jan., 1988 | JP | .
|
3-72371 | Mar., 1991 | JP | .
|
6-043690 | Feb., 1994 | JP.
| |
6-118694 | Apr., 1994 | JP.
| |
6-301232 | Oct., 1994 | JP | .
|
6-348056 | Dec., 1994 | JP.
| |
7-333890 | Dec., 1995 | JP.
| |
9-080817 | Mar., 1997 | JP.
| |
9-179347 | Jul., 1997 | JP.
| |
Primary Examiner: Goodrow; John
Attorney, Agent or Firm: Fish & Richardson P.C.
Claims
What is claimed is:
1. A method for the production of a flash fixing toner containing at least
a binding resin, a coloring agent, and an infrared absorbent, which method
is characterized by the steps of blending a master batch containing said
infrared absorbent at a concentration 3-50 times as thick as that intended
to be incorporated ultimately in the toner, with other toner components,
thereby forming a toner composition containing said infrared absorbent at
a requested concentration, melting and kneading said toner composition,
cooling the molten toner composition, and then pulverizing the solidified
toner composition.
2. A method according to claim 1, wherein said infrared absorbent has an
maximum absorption wavelength in the range of 750 nm-1100 nm.
3. A method according to claim 1 or claim 2, wherein said infrared
absorbent is incorporated in said toner composition at a ratio in the
range of 0.01 wt. %-5 wt. % based on the total amount of said toner
composition.
Description
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to a method for the production of a flash fixing
toner and a master batch for use in the method of production. More
particularly, this invention relates to the technique for producing a
flash fixing toner containing an infrared absorbent.
2. Background Art
For the operation of fixing an image on a material for printing in the
electrophotography, the heat roll system has been mainly used heretofore.
Since this system contemplates forming an image with a toner on a material
for printing such as paper and passing the material carrying the image of
toner thereon between opposed heating rolls thereby causing the toner to
be deposited fast on the material by thermo-compression bonding, however,
it is prone to such problems as exposing a fixing part thereof to the
possibility of being clogged, suffering the formed image to be crushed and
consequently degrading the resolution thereof, and imposing a limit on the
kind of material for printing.
The flash fixing system constitutes itself one version of the non-contact
fixing system and proves an excellent fixing system free from the problems
encountered by the heat roll system as described above. Since this system
requires to fix the toner by the fact that the component in the toner
absorbs the light of a xenon flash lamp, particularly the infrared ray,
however, it permits only defective fixation of a color toner which
profusely uses a coloring material possessing no or only feeble ability to
absorb the infrared ray.
As a means for solving the problem of this defective fixation,
JP-A-63-161,460 has proposed an idea of causing an infrared absorbent
having a light absorption peak at a wavelength in the range of 800-1100 nm
to be incorporated by dispersion in the flash fixing toner.
The manufacture of a toner is generally carried out by a continuous
procedure which comprises premixing a toner composition comprising a
binding resin, a coloring agent, and an electric charge controlling agent
in a powder mixing device such as a Henschel mixer, then continuously
feeding the resultant mixture to a kneading device such as a biaxial
extruding device, melting and kneading the mixture therein thereby
inducing dispersion of the additives such as the coloring agent in the
binding resin, and pulverizing and classifying the formed blend. The
degree with which such additives as the coloring resin are dispersed in
the binding resin by the dispersing work and the uniformity of the
concentration of the produced dispersion are important factors which
affect the solid state properties of the toner.
In the flash fixing toner formed by incorporating therein the
aforementioned infrared absorbent, since the degree of dispersion and the
inconsistency of uniformity of the infrared absorbent in the toner are
factors directly bearing on the fixing of the toner, the degree of
dispersion and the uniformity of concentration to be expected of this
toner will be very high.
Since the infrared absorbent is incorporated in the toner composition in a
small amount as compared with the binding resin, the coloring agent, etc.,
it is very difficult to render constant the concentration of the infrared
absorbent in the toner composition which is continuously melted, kneaded,
and extruded during the manufacture of the toner even when the premixing
work is carried out thoroughly during the production of the toner.
Further, since the productivity of the toner constitutes itself a very
important point, the melting and kneading time to be spent as in the
biaxial extruding device during the course of the kneading mentioned above
is limited and no longer deserves to be called sufficient for fine
dispersion of the infrared absorbent.
The defective dispersion and the ununiform concentration of the infrared
absorbent not merely cause inferior fixing of the toner as described
above. The infrared absorbent, when suffered to disperse in a localized
state, tends to absorb the flash light and emit excess heat and possibly
compels the toner part to form voids (white spots in image). In addition
to the problem of the ability to absorb the infrared ray, the problem of
the charging property to be exhibited to the toner inevitably arises from
the structure, the functional group, etc. of the compound of the infrared
absorbent.
DISCLOSURE OF INVENTION
With respect to the flash fixing toner depicted above, the desirability of
developing a technique for attaining uniform and fine dispersion of an
infrared absorbent in a toner composition comprising a binding resin, a
coloring agent, a charge controlling agent, etc. has been finding growing
approval.
This invention, therefore, has for an object thereof the provision of an
improved method for the production of a flash fixing toner. This invention
has a further object of providing a method for the production of a flash
fixing toner which permits an infrared absorbent to be uniformly and
finely dispersed in a toner composition comprising a binding resin, a
coloring agent, and a charge controlling agent. This invention has another
object of providing a method of production which permits production of a
flash fixing toner having a high capacity for absorption of infrared ray,
exhibiting a highly satisfactory flash fixing property, and providing
economically advantageous.
The present inventors, after performing diligent studies successively with
a view to attaining the objects mentioned, have discovered that when a
toner is produced by preparing a master batch containing an infrared
absorbent intended for incorporation in a flash fixing toner at a
concentration 3-50 times the final concentration of the infrared absorbent
in the flash fixing toner, compounding this master batch with toner
components such as a binding resin and a coloring agent by a prescribed
formula, then premixing them, and continuously feeding the resultant
mixture to a biaxial extruding device, the toner to be produced is allowed
to have the infrared absorbent finely dispersed therein and have the
concentration or distribution of the infrared absorbent kept uniform
between the adjoining toner particles and within the individual toner
particles. The present invention has been perfected as a result.
This invention which accomplishes the various objects mentioned above
concerns a method for the production of a flash fixing toner containing at
least a binding resin, a coloring agent, and an infrared absorbent, which
method is characterized by blending a master batch, which contains an
infrared absorbent intended for incorporation in the toner at a
concentration 3-50 times as thick as the final concentration of the
infrared absorbent in the toner, with other toner components, thereby
forming a toner composition containing the infrared absorbent at a
requested concentration, melting and kneading the toner composition,
cooling the molten toner composition, and then pulverizing the solidified
toner composition.
This invention further discloses a method for the production of a flash
fixing toner mentioned above, wherein the infrared absorbent is an
infrared absorbent having a maximum absorption wavelength in the range of
750 nm-1100 nm.
This invention further discloses a method for the production of a flash
fixing toner mentioned above, wherein the infrared absorbent is
incorporated at a ratio in the range of 0.01 wt. %-5 wt. % of the total
amount of the toner composition.
The objects mentioned above are further accomplished by a master batch of
infrared absorbent for use in a flash fixing toner, characterized by
having the infrared absorbent which is dissolved in a resin component
being to be incorporated in the toner and which has a concentration in the
range of 0.5-15 wt. % of the total amount of the master batch.
The objects mentioned above are further accomplished by a master batch of
infrared absorbent for use in a flash fixing toner, characterized by
having the infrared absorbent which is dispersed in the form of particles,
not more than 0.5 .mu.m in particle diameter, in a resin component being
to be incorporated in the toner and which has a concentration in the range
of 0.5-35 wt. % of the total amount of the master batch.
BEST MODE FOR CARRYING OUT THE INVENTION
Now, this invention will be described more specifically below by reference
to preferred embodiments of the invention.
Infrared absorbent
The infrared absorbent which can be used in the present invention imposes
no particular restriction but requires only to be capable of absorbing the
infrared ray. From the viewpoint of efficiently absorbing the light
issuing from a xenon flash lamp which is a typical light source in the
flash fixing and emitting heat consequently, the infrared absorbent
requires to have a maximum absorption wavelength preferably in the range
of 750-1100 nm, more preferably in the range of 800-1100 nm.
As concrete examples of the infrared absorbent, cyanine compounds,
diimonium compounds, aminium compounds, Ni complex compounds,
phthalocyanine compounds, anthraquinone compounds, and naphthalocyanine
compounds may be cited.
As commercially available versions of such infrared absorbents, Kayasorb
IR-750, IRG-002, IRG-003, IRG-022, IRG-023, IR-820, CY-2, CY-4, CY-9,
CY-10, CY-17, and CY-20 made by Nippon Kayaku Co., Ltd. and
bis(1,2-diphenylecene-1,2-dioctyl) nickel may be cited.
Further, the infrared absorbent is preferred to be capable of being
dissolved or finely dispersed in the resin component destined to form a
matrix in the manufacture of a master batch as described specifically
herein below because this capability can be expected to improve the
uniformity of distribution of the concentration or dispersion of the
infrared absorbent between the toner particles and within the individual
toner particles in the finally produced flash fixing toner. When the
infrared absorbent is dissolved in the binding resin of the toner, the
infrared absorbent is enabled to manifest thoroughly the inherent ability
thereof and, even if incorporated only in a minute amount, still enabled
to fuse efficiently the binding agent by the action of heat generation
during the course of flash fixing because the infrared absorbent
incorporated in the binding resin is dispersed therein on a molecular
level.
The infrared absorbent which can be dissolved or finely dispersed in the
resin component as described above is not easily set forth generally
because the solubility thereof is dominated by the kind of the resin
component to be used in the master batch. As concrete examples of the
infrared absorbent, however, those of the various kinds of compounds of
the group enumerated above which have incorporated such functional groups
as shown below for the purpose of acquiring improved solubility may be
cited.
##STR1##
(wherein R.sup.1 -R.sup.4 independently stand for an alkyl group of C1-C20,
a phenyl group, a tolyl group, a xylyl group, a naphthyl group, an
ethylphenyl group, a propylphenyl group, a butylphenyl group, or a
naphthyl group).
of the commercially available infrared absorbents cited above, those which
exhibit highly satisfactory solubility or fine dispersibility to the resin
component include Kayasorb IRG-002, IRG-003, and CY-10, for example.
Among other infrared absorbents which are usable for the present invention,
those which are represented by the following general formula (I) may be
cited as particularly preferable examples.
The infrared absorbents formed of such phthalocyanine type compounds as
represented by the general formula (I) manifest highly satisfactory
compatibility with such resins which are usable as the binding resin for
the flash fixing toner and can be distributed in a dissolved state or a
finely dispersed state in the resin.
##STR2##
(wherein at least one of the substituents, X.sup.1 -X.sup.16, is NH-R
(providing that R stands for an alkyl group of 1-8 carbon atoms or, a
nonsubstituted or optionally substituted aryl group, preferably a
nonsubstituted or optionally substituted phenyl group) and M stands for a
nonmetal, a metal, a metal oxide, a metal carbonyl, or a metal
halogenide).
The metals represented by M in the compounds of the general formula (I)
include copper, zinc, cobalt, nickel, iron, vanadium, titanium, indium,
aluminum, tin, gallium, and germanium, for example and the metal
halogenides represented by M include fluorides, chlorides, and bromides,
for example. The central atoms or atomic groups of M are preferred to be
possessed of copper, zinc, cobalt, nickel, iron, vanadyl, titanyl,
chloroindium, tin chloride, gallium chloride, dichlorogermanium, indium
iodide, aluminum iodide, gallium iodide, cobalt carbonyl, or iron
carbonyl. Particularly, those which are possessed of vanadyl or tin
chloride prove especially preferable.
In the general formula (I), the substituents, X.sup.1 -X.sup.16, in the
aromatic ring of the phthalocyanine skeleton are preferred to include at
least one, preferably not less than three, and more preferably four-ten,
NH-R groups.
As concrete examples of the NH-R substituent, alkyl amino groups such as
methyl amino, ethyl amino, p-propyl amino, isopropyl amino, n-butyl amino,
isobutyl amino, tert-butylamino, n-pentylamino, and n-octylamino; and aryl
amino or substituted aryl amino groups such as anilino, o-toluidino,
p-toluidino, m-toluidino, 2,4-xylidino, 2,6-xylidino, 2,4-ethyl anilino,
2,6-ethyl anilino, o-methoxy anilino, p-methoxy anilino, m-methoxy
anilino, o-ethoxy anilino, p-ethoxy anilino, m-ethoxy anilino, 2,4-ethoxy
anilino, 2,6-ethoxy anilino, o-fluoro anilino, p-fluoro anilino,
tetrafluoro anilino, and p-ethoxycarbonyl anilino may be cited.
The other substituents that are allowed to occur as the substituents,
X.sup.1 -X.sup.16, in the general formula (I), hydrogen atom, halogen
atoms, and the groups represented by the following general formulas
##STR3##
(wherein R.sup.1 and R.sup.2 independently stand for an alkyl group of 1-8
carbon,atoms, W stands for hydrogen atom, an alkyl group of 1-4 carbon
atoms, an alkoxyl group of 1-4 carbon atoms, or a halogen, and d and e
independently stand for an integer of 1-5) are included.
The term "alkyl group of 1-4 carbon atoms" as used herein means amethyl
group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl
group, an isobutyl group, and a tert-butyl group. The term "alkyl group of
1-8 carbon atoms" means a linear or branched pentyl group, a linear or
branched hexyl group, a linear or branched heptyl group, and a linear or
branched octyl group in addition to the alkyl groups mentioned above. The
term "alkoxyl group of 1-4 carbon atoms" means a methoxyl group, an
ethoxyl group, an n-propoxyl group, an n-butoxyl group, an isobutoxyl
group, and a tert-butoxyl group. The term "acyl group of 1-4 carbon atoms"
means a formyl group, an acetyl group, a propionyl group, a butyryl group,
and an isobutyryl group.
The halogen atoms as other substituents include fluorine atom, chlorine
atom, bromine atom, and iodine atom. Among other halogen atoms, fluorine
atom and chlorine atom prove preferable and fluorine atom proves
particularly preferable. The possession of a fluorine atom as a
substituent can be expected to improve the solubility of the infrared
absorbent.
As concrete examples of the other substituent represented by the general
formula (1), phenoxy, o-methyl-phenoxy, o-methoxy-phenoxy,
o-fluoro-phenoxy, tetrafluorophenoxy, p-methyl-phenoxy,
andp-fluoro-phenoxy may be cited.
As concrete examples of the other substituent represented by the general
formula (2), phenylthio, o-methyl-phenylthio, o-methoxy-phenylthio,
o-fluoro-phenylthio, tetrafluorophenylthio, and p-methyl-phenylthio may be
cited.
As concrete examples of the other substituent represented by the general
formula (3), methoxy, ethoxy, p-propyloxy, isopropoxy, n-butoxy,
isobutoxy, tert-butoxy, n-pentyloxy, and n-octyloxy may be cited.
As concrete examples of the other substituent represented by the general
formula (4), methylthio, ethylthio, p-propylthio, isopropylthio,
n-butylthio, isobutylthio, tert-butylthio, n-pentylthio, andn-octylthio
may be cited.
In the phthalocyanine type compound represented by the 9 general formula
(I), it suffices that at least one, preferably not less than three, and
particularly preferably four to ten, of the 16 substituents, X.sup.1
-X.sup.16, are those represented by NH-R as mentioned above. Further, it
is favorable that the central atom or central atomic group represented by
M in the general formula (I) is vanadyl or tin chloride. It is further
favorable that the positions other than the positions of the substituents
represented by NH-R are invariably occupied by fluorine atoms or
substituents represented by the general formulas (1), (2), (3), or (4)
mentioned above. While the possession of the substituents represented by
NH-R and further the possession of VO or SnCl.sub.2 as the central metal
atom M are advantageous because they can be expected to improve the
solubility of the phthalocyanine type compound in the binding resin and
allow shift of the maximum absorption peak to the greater wavelength side
in the range of wavelength of 750-1100 nm, the inclusion of fluorine atoms
or substituents represented by the general formula (1), (2), (3), or (4)
mentioned above in the substituents other than those mentioned above is
particularly advantageous because it can be expected to improve the
solubility further or allow further shift of the maximum absorption peak
to the greater wavelength side. Of course, the remainder substituents
mentioned above (except the hydrogen atom) can also contribute to improve
the solubility of the compound in the binding resin and/or allow the
maximum absorption peak to be shifted as requested toward the greater
wavelength side in the range of wavelength of 750-1100 nm, although the
degree of contribution for such effects would be varied with the kind of
substituents.
Among the phthalocyanine type compounds that are represented by the general
formula (I), those which are represented by the following general formula
(II) or (III) prove more advantageous. Among the compounds of these
general formulas (II) and (III), those represented by the general formula
(III) prove especially advantageous.
##STR4##
(wherein Y stands for an alkyl or alkoxyl group of 1-4 carbon atoms and a
for 1 or 2.)
##STR5##
(wherein Z stands for a nonsubstituted or optionally substituted phenylthio
group, a nonsubstituted or optionally substituted phenoxy group, an
alkoxyl group of 1-8 carbon atoms, an alkylthio group of 1-8 carbon atoms,
or a fluorine atom, particularly preferably a fluorine atom, and b for an
integer of 6-10.).
As preferred, though only a little, concrete examples of the phthalocyanine
type compound represented by the general formula (I),
octakis(anilino)-octafluorovanadyl phthalocyanine,
octakis-(anilino)-octakis(phenylthio)vanadyl phthalocyanine,
4-tetrakis-(anilino)-3,5,6-dodecafluorotin chloride
phthalocyanine,4-tetra-kis(o-ethoxyanilino)-3,5,6-dodecafluoro tin
chloride phthalo-cyanine, 4-tetrakis(2,6-ethylanilino)-3,5,6-dodecafluoro
tin chloride phthalocyanine, and
4-tetrakis(2,4-dimethoxyanilino)-3,5,6-dodecafluoro tin chloride
phthalocyanine may be cited, but not limited to. In the designations of
these compounds, the 4 and 5 positions of the substitution of the matrix
structure indicate the substituents, X.sup.1, X.sup.4, X.sup.5, X.sup.8,
X.sup.9, X.sup.12, X.sup.13, and X.sup.16 and the 3 and 6 positions
thereof indicate the substituents, X.sup.2, X.sup.6, X.sup.7, X.sup.10 ,
X.sup.11, and X.sup.15.
Since she flash fixing, unlike the heat roll fixing, effects the fixation
of the toner by absorbing the light emitted from a xenon flash lamp and
generating heat consequently, the site of fixation instantaneously reaches
a temperature in the approximate range of 300.degree. C.-600.degree. C. If
the temperature of the infrared absorbent to start yielding to thermal
decomposition or the temperature thereof to withstand thermal degradation
is unduly low, the gas arising from the decomposition will possibly compel
the fixed image to sustain voids (white spots in image). The temperature
of the infrared absorbent to be used in the present invention, therefore,
is required to have a temperature for withstanding thermal degradation of
not less than 230.degree. C., preferably not less than 250.degree. C., and
most desirably not less than 300.degree. C.
Master batch of infrared absorbent
In the method for the production of the flash fixing toner according to the
present invention, the infrared absorbent of the quality described above
is used in the form of a master batch when it is incorporated as one
component in the toner composition.
The master batch under discussion uses as a matrix thereof the resin
component to be incorporated in the flash fixing toner and has the
infrared absorbent of the aforementioned quality incorporated as uniformly
dispersed or dissolved in the matrix.
The concentration of the infrared absorbent in the master batch of this
nature, though variable to a certain extent with the specific mode of
embodiment because the solubility or dispersibility thereof varies with
the kind of infrared absorbent and the kind of resin component to be used
and the combination of these two components, is generally required to fall
in the range of 0.5-35 wt. %, preferably 1-20 wt. %, of the total amount
of the master batch. If the concentration of the infrared absorbent in the
master batch is less than 0.5 wt. %, the time of treatment required for
the infrared absorbent to be uniformly distributed at such a low
concentration in the resin matrix will be inevitably elongated.
Conversely, if the concentration exceeds 35 wt. %, the concentration of
the infrared absorbent will be too high for the infrared absorbent to be
efficiently dissolved or finely dispersed in the entire volume thereof in
the matrix.
When the master batch is in such a mode that the infrared Iabsorbent may
exist in a dissolved state in the resin matrix, the infrared absorbent is
required to account for a ratio in the range of 0.5-15 wt. %, preferably
1-10 wt. %, to the total amount of the master batch on account of the
restriction which is imposed by the solubility on the resin component of
the infrared absorbent.
In contrast, when the master batch of the infrared absorbent according to
this invention is in such a mode that the infrared absorbent may exist in
a dispersed state in the resin matrix, the infrared absorbent contained in
the master batch at the aforementioned concentration in the range of
0.5-35 wt. %, preferably 1-20 wt. %, is required to be finely dispersed in
the form of particles having diameters of not more than 0.5 .mu.m,
preferably not more than 0.3 .mu.m, and more desirably not more than 0.1
.mu.m.
The infrared absorbent, depending on the kind thereof, can be perfectly
dissolved in the resin component of the toner composition at a use
concentration in the toner composition during the final manufacture of the
flash fixing toner such as, for example, a concentration in the
approximate range of 0.01-5 wt. %. If the concentration reaches a level
higher than the upper limit of the range mentioned above or exceeds the
saturated concentration at the end of the manufacture of the master batch,
however, the possibility may arise that the undissolved part of the
infrared absorbent will persist in a granular form in the resin matrix.
The master batch of the infrared absorbent of the present invention, even
when compelled by the relation between the amount of incorporation and the
degree of solubility to assume a state having part of the infrared
absorbent dissolved in the resin matrix and the rest thereof dispersed in
the form of undissolved particles, can be used without any particular
problem and can be embraced in the dispersed type mentioned above. Again
in this case, it is proper that the infrared absorbent is contained in the
master batch at a concentration in the range of 0.5-35 wt. %, preferably
1-20 wt. %, based on the total amount of the master batch and that the
dispersed particles or the undissolved particles of the infrared absorbent
having diameters of not more than 0.5 .mu.m, preferably not more than 0.3
.mu.m, and more desirably not more than 0.1 .mu.m are finely dispersed.
The concentration of the infrared absorbent in the master batch is required
from the viewpoint of the manufacture of the flash fixing toner to be 3-50
times, preferably 3-30 times, the concentration of the infrared absorbent
added to the toner composition. If the concentration of the infrared
absorbent in the master batch is less than three times that of the
infrared absorbent to be incorporated, the shortage will bring such
disadvantages as causing an undue addition to the amount of the master
batch, suffering the production of the master batch and consequently the
manufacture of the toner to consume much time, and boosting the cost of
the toner. If the concentration is more than 50 times that of the infrared
absorbent to be incorporated, the excess will cause an undue addition to
the concentration of the infrared absorbent and possibly disable thorough
elimination of the inferior dispersion of the infrared absorbent in the
produced toner and the lack of uniformity of the concentration.
The resin component which is fated to form the matrix of the master batch
of the infrared absorbent according to the present invention imposes no
particular restriction but requires only to be infallibly incorporated in
the flash fixing toner aimed at in an amount at least larger than the
amount of the infrared absorbent to be incorporated. The most typical and
favorable resin component is a resin which functions as the binding resin
which constitutes itself a main component of the toner. As other examples
of the proper resin component, the wax incorporated in the toner, the
resin used for the adjustment of the electric charge, and the resin
incorporated for the purpose of improving the special quality of the
binding resin may be cited. Further, the resin which, though incapable of
improving the special quality of the binding resin, has compatibility with
or ready dispersibility in the binding resin can be used as the matrix of
the master batch the resin, so long as the resin brings no serious
degradation of the special quality.
As concrete examples of the resin which can be used as the matrix of the
master batch of the infrared absorbent, the resins of the polystyrene
type, the resins based on the copolymers of styrene with (meth)acrylates,
acrylonitrile, or maleic esters, the resins of the poly(meth)acrylic ester
type, the resins of the polyester type, polyamide type, epoxy type, phenol
type, hydrocarbon type, and rosin, modified rosin, terpene resin, and
pinene resin may be cited, though not exclusively. These resins can be
used either singly or in the form of a combination of two or more members.
Among these resins, the resin that is identical with the resin to be
incorporated in the toner composition as the binding resin of the flash
fixing toner to be ultimately produced proves particularly favorable.
Specifically, the polyester resin or the epoxy resin of bisphenol
A/epichlorohydrin which constitutes itself a proper binding resin for the
flash fixing toner as will be specifically described herein below proves
favorable.
Various methods can be adopted for the production of the master batch
containing the kind of infrared absorbent mentioned above. Several of
these methods are cited by way of examples. The production contemplated by
this invention does not need to be limited to the methods cited below but
may be effected by any method which does not depart from the spirit of
this invention.
A method which comprises melting and kneading the infrared absorbent and
the resin component with a melting and kneading device such as, for
example, a biaxial extruding device, a three-roll kneader, or a Banbury
mixer, a method which comprises dissolving the infrared absorbent in
advance in a solvent, adding the resultant solution to the resin
component, and melting and kneading the produced mixture with the melting
and kneading device mentioned above while removing the solvent, and a
method which comprises finely dispersing the infrared absorbent in advance
in a solvent by the use of a wet dispersing device such as, for example, a
sand mill, colloid mill, or ball mill and the adding the product of the
fine dispersion to the resin component and melting and kneading the
resultant mixture with the melting and kneading device mentioned above
while removing the solvent may be cited. Incidentally, during the work of
melting and kneading with the melting and kneading device mentioned above,
the viscosity of the resin component properly falls in the range of
10.sup.3 P-10.sup.5 P (poises), preferably in the range of
3.times.10.sup.3 P-4.times.10.sup.4 P.
The master batch can be manufactured by a method of polymerization instead
of the aforementioned methods which resort to the work of melting and
kneading. Specifically, this method consists in causing a polymerizing
monomer capable of forming a required resin component by polymerization to
be polymerized in the presence of the infrared absorbent. The production
of the master batch by this method of polymerization can be carried out by
varying forms of polymerization such as, for example, solution
polymerization, bulk polymerization, suspension polymerization, emulsion
polymerization, and dispersion polymerization so long as the infrared
absorbent is dissolved or finely dispersed and allowed to assume a
uniformly distributed state in the resin component to be obtained by the
polymerization. Among other forms of polymerization cited above,
particularly the suspension polymerization, the emulsion polymerization,
and the dispersion polymerization prove commendable.
The polymerizing monomers that can be used in the suspension
polymerization, emulsion polymerization, and dispersion polymerization are
not particularly limited. As concrete examples of the polymerizing
monomer, styrene type monomers such as styrene, o-methyl styrene, m-methyl
styrene, p-methyl styrene, .alpha.-methyl styrene, p-methoxy styrene,
p-tert-butyl styrene, p-phenyl styrene, o-chlorostyrene, m-chlorostyrene,
and p-chlorostyrene; (meth)acrylic ester type monomers such as methyl
acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl
acrylate, stearyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl
acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl
methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate; olefin
type monomers such as ethylene, propylene, and butylene; and various vinyl
type polymers such as acrylic acid, methacrylic acid, vinyl chloride,
acrylonitrile, acryl amide, methacryl amide, and N-vinyl pyrrolidone may
be cited. These polymerizing monomers may be used either singly or in the
form of a combination of two or more members.
As concrete examples of the dispersant or emulsifier to be used in the
suspension polymerization, dispersion polymerization, and emulsion
polymerization, macromolecular dispersants such as polyvinyl alcohol,
gelatin, tragacanth, starch, methyl cellulose, carboxy methyl cellulose,
hydroxyethyl cellulose, sodium polyacrylate, sodium polymethacrylate, and
polyvinyl pyrrolidone; surfactants such as sodium dodecylbenzene
sulfonate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium
octyl sulfate, sodium allyl-alkyl-polyether sulfonate, sodium oleate,
sodium laurate, sodium caprylate, sodium caproate, sodium stearate,
potassium oleate, sodium 3,3'-disulfodiphenyl
urea-4,4'-diazo-bis-amino-8-naphthol-6-sulfonate,
ortho-carboxy-benzene-azo-dimethyl aniline, sodium
2,2',5,5'-tetramethyl-triphenyl
methane-1,1'-diazo-bis-.beta.-naphthol-disulfonate, sodium
alkylnaphthalene sulfonate, sodium dialkylsulfosuccinate, sodium
alkyldiphenyl ether disulfonate, sodium polyoxyethylene alkyl sulfate,
polyoxyethylene alkylether sulfuric acid triethanol amine, ammonium
polyoxyethylene alkylphenyl ether sulfate, sodium alkylsulfonate, sodium
salts of .beta.-naphthalene sulfonic acid-formalin condensate, sodium
salts of special aromatic sulfonic acid-formaline condensate, special
carboxylic acid type macromolecular surfactants, polyoxyethylene lauryl
ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether,
polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether,
polyoxyethylene sorbitan alkylate, lauryl trimethyl ammonium chloride,
stearyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride,
distearyl dimethyl ammonium chloride, and alkylbenzyl dimethyl ammonium;
and alginates, zein, casein, barium sulfate, calcium sulfate, barium
carbonate, magnesium carbonate, calcium phosphate, talc, clay,
diatomaceous earth, bentonite, titanium hydroxide, sodium hydroxide, and
metal oxide powders may be cited.
The initiators of the oil-soluble peroxide type or the azo type can be
generally adopted as polymerization initiators for use in the suspension
polymerization and the dispersion polymerization. As typical examples of
the initiators, peroxide type initiators such as benzoyl peroxide, lauroyl
peroxide, octanoyl peroxide, benzoyl orthochloroperoxide, benzoyl
orthomethoxyperoxide, methylethyl ketone peroxide, diisopropyl peroxy
dicarbonate, cumene hyrdoperoxide, cyclohexane peroxide, t-butyl
hydroperoxide, and diisopropyl benzene hydroperoxide; and
2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethyl valero-nitrile),
2,2'-azobis(2,3-dimethylbutyronitrile),
2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis
(2,3,3-trimethylbutyronitrile), 2,2'-azobis (2-isopropylbutyronitrile),
1,1'-azobis (cyclohexane-1-carbonitrile),
2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1- (carbamoylazo)
isobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and
dimethyl-2,2'-azobisisobutyrate may be cited. As concrete examples of the
water-soluble initiator for use in the emulsion polymerization,
persulfates such as sodium persulfate, potassium persulfate, and ammonium
persulfate, organic peroxides such as tertiary isobutyl hydroperoxide,
cumene hydroperoxide, and paramethane hydroperoxide, and hydrogen peroxide
may be cited. These polymerizing monomers are properly used at a ratio in
the range of 0.01-20 wt. %, particularly 0.1-10 wt. %, to the polymerizing
monomer.
The time and the method of incorporation of the infrared absorbent in the
polymerizing monomer composition during the production of the master batch
by the method of polymerization described above are not particularly
limited. The method for dispersion or dissolution of the infrared
absorbent in the polymerizing monomer is not particularly restricted.
These methods are properly selected so that the infrared absorbent may be
present uniformly in the produced polymer and the state of this presence
may be in a dissolved state or finely dispersed state.
Specifically, the incorporation can be effected at any of the steps of
manufacturing the polymerizing monomer composition in a polymerization
system, dispersing the polymerizing monomer composition in a dispersion
medium, subjecting the polymerizing monomer composition to a
polymerization reaction, and optionally subjecting the product of the
polymerization to a coagulating treatment.
For the purpose of dissolving the infrared absorbent in the polymerizing
monomer composition, the simplest method of dissolving the infrared
absorbent in a polymerizing monomer or the method of dissolving the
infrared absorbent by melting and kneading it in a resin which is soluble
in a polymerizing monomer are available. By melting and kneading the
infrared absorbent in advance in a resin soluble in a polymerizing monomer
and then adding the resin now containing the infrared absorbent to the
polymerizing monomer and dissolving it therein, even the infrared
absorbent which inherently exhibits no or only meager solubility to the
polymerizing monomer can be dissolved in the polymerizing monomer owing to
the fact that the resin manifests the function of a surfactant.
As means for dispersing the infrared absorbent, various methods are
available. As a typical example of the means, a method which comprises
adding the infrared absorbent in a finely dispersed state to such
polymerizing monomer, solvent, aqueous medium, and resin as are used in
the polymerizing system or the system for coagulating treatment may be
cited. In the components mentioned above, the resin does not mean a
polymer which is obtained in consequence of the polymerization of a
polymerizing monomer composition but means a resin which can be
incorporated in the polymerizing monomer composition of this quality and
can be dissolved in this polymerizing monomer composition or a resin which
can be added to and dissolved in a solvent to be used in the
polymerization system.
As typical examples of the method for fine dispersion of the infrared
absorbent in such liquid components as polymerizing monomer and solvent, a
method resorting to such a high-speed shearing type dispersing device as
homomixer, biomixer, or Ebara milder, a method resorting to such an
attrition type dispersing device as colloid mill or homomix line mill, and
a method resorting to such a media mill as ball mill, side grind mill,
pearl mill, or attriter may be cited.
As a means for dispersion as in the resin, a method which comprises melting
and kneading the infrared absorbent with the resinby the use of arollmill,
kneader, pressure kneader, Banbury mixer, Labo plast mill, or uniaxial or
biaxial kneading and extruding device thereby finely dispersing the
infrared absorbent in solid components such as the resin may be cited.
Though the degree with which the treatment for fine dispersion of the
infrared absorbent is carried out is governed by the kinds of polymerizing
monomer, solvent, aqueous medium, resin, etc. in which the infrared
absorbent is incorporated and treated for dispersion, it is properly set
such that the infrared absorbent, when dispersed, may form particles
having diameters not preceding 0.5 .mu.m, preferably falling in the
approximate range of 0.01-0.3 .mu.m.
The master batch of the infrared absorbent according to this invention is
formed by adopting as a matrix thereof the resin component incorporated in
the toner and causing the infrared absorbent of the quality mentioned
above to be dissolved or finely dispersed in the matrix as described
above. This master batch is allowed to incorporate in advance therein
other additives such as, for example, a wax component and an electric
charge controlling agent which are incorporated in minute amounts
similarly to the infrared absorbent in the flash fixing toner to be
eventually manufactured.
The form of the master batch is not particularly limited. The master batch
may assume arbitrarily any of such forms as lumps, powder, scales, and
pellets. Among other forms cited above, powder and pellets prove
particularly favorable.
Binding resin
Now, the components other than the infrared absorbent which are used in the
method for the production of the flash fixing toner of this invention will
be cited below by way of example.
The binding resin does not need to impose any particular restriction. As
concrete examples of the binding resin, the resins of the polystyrene
type, the type of copolymers of styrene with (meth)acrylic esters,
acrylonitrile, or maleic esters, the poly(meth)acrylic ester type,
thepolyester type, the polyamide type, the epoxy type, the phenol type,
the hydrocarbon type, and the petroleum type may be cited. Polyester
resins or epoxy resins such as bisphenol A/epichlorohydrin are preferable
examples. These resins may be used either singly or in the form of a
mixture of two or more members and may be used in combination with other
resins and additives.
Coloring agent
The coloring agent to be used may be selected arbitrarily from varying
coloring agent known heretofore. As concrete examples of the coloring
agent, pigments or dyes including black coloring agents such as carbon
black, furnace black, and acetylene black, yellow coloring agents such as
chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chrome
yellow, naphthol yellow, hanza yellow, pigment yellow, benzidine yellow,
permanent yellow, quinoline yellow, and anthrapyrimidine yellow, orange
coloring agents such as permanent orange, molybdenum orange, Valcan fast
orange, benzine orange, and indanthrene brilliant orange, brown coloring
agents such as iron oxide, amber, and permanent brown, red coloring agents
such as iron oxide red, rose iron oxide red, antimony powder, permanent
red, fire red, brilliant carmine, lightfast red toner, permanent carmine,
pyrazolone red, Bordeaux, helio Bordeaux, rhodamin lake, DuPont oil red,
thioindigo red, thioindigomaroon, and watching red strontium, purple
coloring agents such as cobalt purple, fast violet, dioxane violet, and
methyl violet lake, blue coloring agents such as methylene blue, aniline
blue, cobalt blue, ceryl amblue, chalco oil blue, nonmetallic
phthalocyanine blue, phthalocyanine blue, ultra marine blue, indanthrene
blue, and indigo, and green coloring agents such as chrome green, cobalt
green, pigment green B, green gold, phthalocyanine green, malachite green
oxalate, and polychromebrome copper phthalo-cyanine may be cited. These
pigments or dyes may be used either singly or in the form of a mixture of
two or more members.
Since the flash fixing toner of this invention is aimed at improving the
flash fixing property by the addition of the infrared absorbent, it
manifests a particularly large effect in the case of a color tone using a
coloring agent other than black.
These coloring agents are properly incorporated in a given toner
composition in an amount in the range of 3-15 parts by weight, based on
100 parts by weight of the binding resin, though this amount is not
critical for this invention.
Other additives
The flash fixing toner of this invention, when necessary, is allowed to
incorporate therein other additives such as wax component, electric charge
controlling agent, and fluidifying agent.
Polyolefin type waxes and natural waxes are usable as the wax component. As
concrete examples of the polyolefin type wax, polyethylene, polypropylene,
polybutylene, ethylene-propylene copolymer, ethylene-butene copolymer,
ethylene-penthene copolymer, ethylene-3-methyl-1-butene copolymer, and
copolymers of olef ins with other monomers such as, for example, vinyl
esters, haloolefins, (meth)acrylic esters, (meth)acrylic acid or
derivatives thereof may be cited. These polyolefin type waxes are
preferred to have weight average molecular weights in the approximate
range of 1000-45000. As concrete examples of the natural wax, carnauba
wax, montan wax, and natural paraffin may be cited.
As concrete examples of the electric charge controlling agent, nigrosin,
monoazo dye, zinc, hexadecyl succinate, alkyl esters or alkyl amides of
naphthoeic acid, nitrohumic acid, N,N-tetramethyl diamine benzophenone,
N,N-tetramethyl benzidine, triazine, and metal complexes of salicylic acid
may be cited. When the flash fixing toner of this invention is in the form
of a color toner using a coloring agent other than black, the electric
charge controlling agent to be used is preferred to have no color or a
light color.
The fluidifying agents which are usable herein include inorganic minute
particles of colloidal silica, hydrophobic silica, hydrophobic titania,
hydrophobic zirconia, and talc and organic minute particles such as
polystyrene beads and (meth)-acrylic resin beads, for example.
Method for production of flash fixing toner
The method for the production of the flash fixing toner according to this
invention is characterized by using the master batch of infrared absorbent
of the kind mentioned above when the infrared absorbent is to be
incorporated in the toner composition by a specific formulation. To be
specific, the toner aimed at is produced by preparing amaster batch
containing the infrared absorbent at a concentration 3-50 times that of
the infrared absorbent to be ultimately incorporated in the toner,
compounding the master batch with such binding resin and coloring agent as
mentioned above optionally in conjunction with other additives which have
been weighed out in prescribed amounts thereby forming a toner composition
containing the infrared absorbent at a requested concentration, melting
and kneading the produced toner composition, cooling the molten toner
composition, then pulverizing the cooled toner composition, and optionally
further classifying the pulverized toner composition. Since the master
batch has the resin component as the matrix thereof, the amounts of the
components in the toner composition ought to be adjusted in due respect of
the function which is expected to be fulfilled by the resin component when
it is incorporated in the toner. When the resin component functions as a
binding resin, for example, it is only natural that the total amount of
the binding resin in the toner composition is the sum of the amount of the
resin component in this master batch and the amount of the resin
separately incorporated as a binding resin.
In the method of production according to this invention, the device to be
used in melting and kneading the toner composition as described above
imposes no restriction particularly but requires only to be capable of
producing a flash fixing toner such that the infrared absorbent may exist
in the ultimately formed binding resin as dissolved or finely dispersed in
the form of particles having a diameter of not more than 0.5 .mu.m,
preferably not more than 0.3 .mu.m, and more preferably not more than 0.1
.mu.m and that the concentration distribution of the infrared absorbent
may be uniform between adjoining toner particles and within individual
toner particles. As concrete examples of the device effectively usable
herein, a roll mill, a kneader, a pressure kneader, a Banbury mixer, a
Labo plast mill, and a uniaxial or biaxial kneading and extruding device
may be cited. It is permissible to adopt a step of premixing the toner
composition by the use of a Henschel mixer, a super mixer, a V blender, or
a tumble blender, as occasion demands, prior to the operation of melting
and kneading mentioned above. The toner composition during the course of
melting and kneading assumes a viscosity in the range of 10.sup.3
P-10.sup.5 P (poises), preferably in the range of 3.times.10.sup.3
P-4.times.10.sup.4 P.
Since the method of production of this invention uses the master batch as
the source of the infrared absorbent as described above, it accomplishes
uniform concentration distribution or dispersion distribution of the
infrared absorbent in the toner composition even by a kneading treatment
performed for a relatively short duration or a kneading treatment
performed in a continuous production.
Shape and use of flash fixing toner
The flash fixing toner to be produced by the method of production according
to this invention has a volume average particle diameter in the
approximate range of 3-15 .mu.m, preferably 5-15 .mu.m, and more
preferably 5-10 .mu.m, though variable with the degree of resolution aimed
at in the process of electrophotography.
If the volume average particle diameter of the toner exceeds 15 .mu.m, the
toner will have too large a particle diameter to permit production of an
image of fully satisfactory resolution. Conversely, if this diameter is
less than 3 .mu.m, the shortage will impair the stability of the produced
image because of low flowability of the toner particles and will cause
fogging and poor cleaning despite the fact that the image has high
resolution.
A xenon flash lamp is used for fixing the flash finishing
electrophotographic toner according to this invention. For the purpose of
this fixation, the xenon flash lamp is preferred to be operated with an
electric input energy per unit area in the range of 1.6-3 J/cm.sup.2. The
toner is used safely so long as the degree of fixation thereof is not less
than 70%. If this degree is less than 70%, however, the fixed toner will
be excoriated by frictional force and suffered to smear other objects
which happen to touch it.
The flash fixing toner of this invention can be used advantageously for
various applications such as, for example, bar code printers, label
printers, tag printers, and printers and copying devices of the Carlson
system or the ion flow system. Particularly in the mode of embodiment in
colored prints, since the flash fixing toner allows inexpensive aprovision
of products which manifest an ideal flash fixing property, it readily
satisfies the demand for coloration of images in such applications as
mentioned above.
EXAMPLES
Now, this invention will be described more specifically below by reference
to working examples thereof. It should be noted, however, that this
invention is not limited to these working examples. Wherever "%" and
"parts" are mentioned herein below, they mean "% by weight" and "parts by
weight" unless otherwise specified.
Example 1
In a Henschel mixer, 10 kg of a master batch composition of infrared
absorbent formed of 100 parts of a polyester resin (made by Kao
Corporation and sold under the trademark designation of "Toughton NE1110")
and 3 parts of an infrared absorbent
(octakis-(anilino)-octakis(phenylthio)vanadyl phthalocyanine) was
thoroughly mixed. Then, the resultant mixture was melted and kneaded in a
MS type pressure kneader (made by Moriyama K.K.) at1000.degree. C. for 30
minutes. Subsequently, the blend was cooled and pulverized with a coarse
pulverizer into particles, not more than 1 mm in diameter, to obtain a
master batch (1) of infrared absorbent. In this master batch, the infrared
absorbent was perfectly dissolved in the polyester resin.
In a Henschel mixer, 10 kg of a toner composition formed of 10.3 parts of
the master batch (1) of infrared absorbent, 90 parts of the same polyester
resin as mentioned above, 5 parts of phthalocyanine blue (made by Toyo Ink
Mfg. Co., Ltd. and sold under the trademark designation of "Rionol
Blue-ES"), and 1 part of an electric charge controlling agent (made by
Orient Kagaku Kogyo K.K. and sold under the trademark designation of
"Bontron E82") was thoroughly mixed. Then the toner composition was fed
continuously to a biaxial extruding device and melt and kneaded therein.
The melt kneaded toner composition was cooled, then pulverized coarsely,
and further pulverized finely with a jet mill. The fine powder
consequently obtained was classified with a wind power classifier to
obtain a blue powder having an average particle diameter of 8.7 .mu.m.
In a Henschel mixer, 100 parts of this blue powder and 0.4% of hydrophobic
silica (made by Nippon Aerosil K.K. and sold under the product code of
"Silica R972") added thereto were uniformly mixed to obtain a toner (1).
The toner (1) obtained as described above was rated with respect to fixing
property, fogging on an image, and voids in a fixed image in accordance
with the methods described herein below. The results are shown in Table 1.
Example 2
A master batch (2) of infrared absorbent was obtained by treating 10 kg of
a master batch composition of infrared absorbent formed of 100 parts of a
styrene-acrylic resin (made by Sanyo Kasei K.K. and sold under the product
code of "TB-1000") and 10 parts of an infrared absorbent (made by Nippon
Kayaku Co., Ltd. and sold under the trademark designation of Kayasoub
CY10") in the same manner as in Example 1. In this master batch, the
infrared absorbent was perfectly dissolved in the styrene-acrylic resin.
A toner (2) was obtained by treating 10 kg of a toner composition formed of
11 parts of the master batch (2) of infrared absorbent, 70 parts of the
styrene-acrylic resin, 20 parts of styrene-acrylic resin (made by Sanyo
Kasei K.K. and sold under the product code of "STl-95"), 7 parts of a red
pigment (made by Toyo Ink Mfg. Co., Ltd. and sold under the trademark
designation of "Lionel Red CP-A"), and 1 part of an electric charge
controlling agent (made by Orient Kagaku Kogyo K.K. and sold under the
trademark designation of "Bontron E84") in the same manner as in Example
1. This toner has an average particle diameter of 9.5 .mu.m.
The toner (2) obtained as described above was rated with respect to fixing
property, fogging on an image, and voids in a fixed image in accordance
with the methods described herein below. The results are shown in Table 1.
Example 3
A master batch (3) of infrared absorbent having an infrared absorbent
dispersed in the form of particles, not more than 0.5 .mu.m in diameter,
was obtained by following the procedure of Example 2 while using 35 parts
of bis (1,2-diphenylecene-1,2-dithiol) nickel in the place of 10 parts of
the infrared absorbent (Kayasoub CY10) and effecting the treatment of
melting and kneading in the same device as in Example 1.
Incidentally, the diameter of the dispersed particles of infrared absorbent
was determined by dissolving a sample of the master batch of infrared
absorbent in toluene and measuring the particle diameters of the infrared
absorbent in the solution with the aid of an optical microscope.
A toner (3) was obtained by following the procedure of Example 2 while
using 13.5 parts of the master batch (3) of infrared absorbent prepared as
described above in the place of 11 parts of the master batch (2) of
infrared absorbent. This toner was found to have an average particle
diameter of 8.5 .mu.m.
The toner (3) obtained as described above was rated with respect to fixing
property, fogging on an image, and voids in a fixed image in accordance
with the methods described herein below. The results are shown in Table 1.
Example 4
A master batch (4) of infrared absorbent was obtained by following the
procedure of Example 1 while using 25 parts of
octakis(anilino)octafluorovanadyl phthalocyanine in the place of 3 parts
of the infrared absorbent, i.e. octakis(anilino)-octakis-(phenylthio)
vanadyl phthalocyanine. In this master batch, the infrared absorbent was
dissolved to fairly a large extent in the polyester resin and part of the
infrared absorbent was found in an undissolved state. The particles of the
dispersed infrared absorbent had diameters not exceeding 0.3 .mu.m.
A toner (4) was obtained by following the procedure of Example 1 while
using 2.5 parts of the master batch (4) of infrared absorbent manufactured
as described above in the place of 10.3 parts of the master batch (1) of
infrared absorbent. This toner was found to have an average particle
diameter of 6.0 .mu.m.
The toner (4) obtained as described above was rated with respect to fixing
property, fogging on an image, and voids in a fixed image in accordance
with the methods described herein below. The results are shown in Table 1.
Example 5
In 800 parts of water having dissolved therein 10 parts of polyvinyl
alcohol (made by Kuraray Co., Ltd. and sold under the product code of
"PVA205"), a polymerizing monomer composition formed by uniformly
dissolving 85 parts of styrene, 15 parts of n-butyl acrylate, 5 parts of
an infrared absorbent [octakis-(anilino)-octakis(phenylthio) vanadyl
phthalocyanine], and 1 part of 2,2'-azobis-butyronitrile (made by Nippon
Hydrazine Kogyo K.K. and sold under the product code of "ABNR") was
stirred with a paddle vane and subjected meanwhile to suspension
polymerization under an atmosphere of nitrogen at 75.degree. C. for eight
hours.
A master batch (5) of infrared absorbent was obtained by separating
consequently formed infrared absorbent-containing resin beads from the
polymerization solution, thoroughly washing the beads, and drying the
washed beads with a hot air drier at 50.degree. C. In this master batch,
the infrared absorbent was perfectly dissolved in the resin matrix.
A toner (5) was obtained by following the procedure of Example 2 while
using 4.4 parts of the master batch (5) of infrared absorbent manufactured
as described above in the place of 11 parts of the master batch (2) of
infrared absorbent. This toner was found to have an average particle
diameter of 7.5 .mu.m.
The toner (5) obtained as described above was rated with respect to fixing
property, fogging on an image, and voids in a fixed image in accordance
with the methods described herein below. The results are shown in Table 1.
Control 1
A toner for comparison (C1) was obtained by following the procedure for the
production of the toner from the toner composition as described in Example
1 while omitting the preparation of the master batch and using 10 kg of a
toner composition formed of 100 parts of a polyester resin (made by Kao
Corporation and sold under the trademark designation of "Toughton
NE1110"), 0.3 part of an infrared absorbent
[octakis(anilino)-octakis(phenylthio) vanadyl phthalocyanine), 5 parts of
phthalocyanine blue (made by Toyo Ink Mfg. Co., Ltd. and sold under the
trademark designation of "Lionol Blue ES"), and 1 part of an electric
charge controlling agent (made by Orient Kagaku Kogyo K.K. and sold under
the trademark designation of "Bontron E82") instead. This toner was found
to have an average particle diameter of 9.0 .mu.m.
The toner for comparison (C1) obtained as described above was rated with
respect to fixing property, fogging on an image, and voids in a fixed
image in accordance with the methods described herein below. The results
are shown in Table 1.
Control 2
A toner for comparison (C2) was obtained by following the procedure for the
production of the toner from the toner composition as described in Example
1 while using 10 kg of a toner composition formed of 80 parts of
styrene-acrylic resin (made by Sanyo Kasei K.K. and sold under the product
code of "TB-1000"), 20 parts of styrene-acrylic resin (made by Sanyo Kasei
K.K. and soldunder theproduct code of "ST-95"), 1 part of an infrared
absorbent (made by Nippon Kayaku Co., Ltd. and sold under the trademark
designation of "Kayasoub CY10"), 7 parts of a red pigment (made by Toyo
Ink Mfg. Co., Ltd. and sold under the trademark designation of "Lionel Red
CP-A"), and 1 part of an electric charge controlling agent (made by Orient
Kagaku Kogyo K.K. and sold under the trademark designation of "Bontron
E84") instead. This toner was found to have an average particle diameter
of 9.3 .mu.m.
The toner for comparison (C2) obtained as described above was rated with
respect to fixing property, fogging on an image, and voids in a fixed
image in accordance with the methods described herein below. The results
are shown in Table 1.
Control 3
A toner for comparison (C3) was obtained by following the procedure of
Control 2 while using 6.9 parts of bis(1,2-diphenylecene-1,2-dithiol)
nickel in the place of 1 part of the infrared absorbent (Kayasoub CY10).
This toner was found to have an average particle diameter of 9.1 .mu.m.
The toner for comparison (C3) obtained as described above was rated with
respect to fixing property, fogging on an image, and voids in a fixed
image in accordance with the methods described herein below. The results
are shown in Table 1.
Referential Example 1
A referential master batch of infrared absorbent (R1) was obtained by
following the procedure of Example 2 while changing the amount of the
infrared absorbent to 60 parts. In this master batch, the infrared
absorbent was dissolved to fairly a large extent in the resin matrix and a
large proportion of the infrared absorbent was found in an undissolved
state. The particles of the infrared absorbent included in a large
proportion crude particles measuring not less than 1 .mu.m in diameter.
Then, a referential toner (R1) was obtained by following the procedure of
Example 2 while using 2.7 parts of the referential master batch of
infrared absorbent (R1) in the place of 11 parts of the master batch of
infrared absorbent (2). This toner was found to have an average particle
diameter of 9.4 .mu.m.
The referential toner (R1) obtained as described above was rated with
respect to fixing property, fogging on an image, and voids in a fixed
image in accordance with the methods described herein below. The results
are shown in Table 1.
Methods of rating State of infrared absorbent in master batch
The infrared absorbents in the master batches obtained in the varying
experiments described above were visually examined to determine their
states of aggregation. Since the infrared absorbents other than the
infrared absorbent used in Example 3 were soluble in a solvent, the
observation of the state of aggregate in the experiments other than
Example 3 was carried out by hot-pressing a given master batch thereby
preparing a film, 0.1 mm in thickness, and observing this film under an
optical microscope.
Test for degree of fixation
A developing agent composed of 4 parts of a toner and 96 parts of a carrier
coated with an acryl-modified silicon resin was set in a commercially
available copying device (made by Toshiba Corporation and sold under the
trademark designation of "Leodry 7610"). A loose image was formed on the
layer of the developing agent and then flash fixed by the use of a xenon
flash lamp.
The flash fixed image was subjected to a tape peeling test using a Scotch
mending tape (made by 3M). The ratio of the image remaining after the tape
separation was reported as the degree of fixation.
The ratio of residual image after the tape separation was determined by
measuring the image density before and after the tape separation and
performing calculation of the following formula using the results of the
measurement.
Degree of fixation (%)=(Image density after the tape separation)/(image
density before the tape separation).times.100
The image density was measured with an instrument (made by A Division
Kollmorgen Corp and sold under the trademark designation of "McBeth
Reflection Densitometer, Model RD514").
Fogging on image
The toner fogging formed on the white image part of a sample was rated by
visual observation of the sample by the use of a magnifying glass at 20
magnifications. The rating was made on the following three-point scale,
wherein
.largecircle.: Absence of toner fogging
.DELTA.: Presence of toner fogging on a level causing no problem
X: Copious problematic presence of toner fogging
Rating of voids in fixed image
The wholly black part of a given fixed image was observed under a
microscope (100 magnifications) to find and rate voids (white spots). The
rating was made on the following four-point scale, wherein
.largecircle.: Absence of discernible void
.DELTA.: Presence of a few discernible voids
X: Presence of numerous discernible voids
-: Not ratable because of absence of fixation
TABLE 1
Toner particle Degree of
Infrared Amount added diameter fixation
Toner absorbent* (PHR) (.mu.m) (%) Fogging
Voids
Example 1 (1) A 0.3 8.7 93
.largecircle. .largecircle.
Example 2 (2) B 1.0 9.5 90
.largecircle. .largecircle.
Example 3 (3) C 3.1 8.8 89
.largecircle. .largecircle.
Example 4 (4) D 0.5 6.0 91
.largecircle. .largecircle.
Example 5 (5) A 0.2 7.5 94
.largecircle. .largecircle.
Control 1 (C1) A 0.3 9.0 56 .DELTA.
.DELTA.
Control 2 (C2) B 1.0 9.3 62 X
.DELTA.
Control 3 (C3) C 6.0 9.1 66 X X
(R1) B 1.0 9.4 85 .DELTA.
X
*A-Octakis(anilino)-octakis(phenylthio)vanadyl phthalocyanine,
.lambda..sub.max 964 nm
B-Kayasoub CY 10, made by Nippon Kayaku Co., Ltd., .lambda..sub.max 799 nm
C-Bis(1,2-diphenylecene-1,2-dithiol)nickel, .lambda..sub.max 869 nm
D-Octakis(anilino)octafluorovanadyl phthalocyanine, .lambda..sub.max 890 nm
Industrial Applicability
This invention, owing to the use of a master batch which, as described
above, contains an infrared absorbent at a concentration 3-50 times that
of the infrared absorbent to be incorporated in the manufacture of a flash
fixing toner, allows the toner, if produced in a continuous process, to
contain the infrared absorbent at a fixed concentration and, at the same
time, permits the infrared absorbent to be finely dispersed in the toner,
and consequently enables the produced toner to acquire such physical
properties as fixing property and electrically charging property in a
stable state. The use of the master batch according to this invention
precludes easy occurrence of voids in the produced image because the
infrared absorbent is dissolved or finely dispersed in the toner
composition. Further, the infrared absorbent contained in the toner
composition in enabled to manifest the function thereof thoroughly,
notwithstanding it is used in a very small amount relative to the amount
of the toner composition.
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